I think the calculation was made that they wanted the IRAQI governing council to make this decision. It is their country, and they have been softening up the area for the last few months trying to convince the regular Iraqis that the fight is not with them, but with the foreign terrorists and the leftover Baathists in their midst.
Good point. This, of course, is the great wildcard here -- DO the Iraqis want to maintain a nation or not? Hope so.